The present invention relates generally to printers and, more particularly, to a label stock cassette and label printer with features which aid installation and securing of the cassette into the printer, and improved label stock delivery during a printing operation.
Label printers commonly utilize a media stock in the form of a roll of a backing material with labels affixed thereto, where the labels can be easily peeled from the backing material after passing by a print head assembly which prints information on the labels. In some printers media cassettes are used to supply the label stock, where the cassette includes a supply roll of label stock and a take up roll which receives a backing material of the label stock after labels have been printed and peeled therefrom. The label stock backing follows an angled path out of an opening in the cassette, around the print head assembly and back into the cassette to the take up roll. If the cassette is removed from the printer before the label stock supply is expended, reinsertion of the cassette is impeded by the need to attain the proper label stock path around the print head assembly. Accordingly, it would be desirable to provide a media cassette which facilitates placement of the label stock around the print head assembly upon insertion into the printer.
The label stock in such printers is typically fed past the print head by a rotatable feed roller which contacts the label stock and presses the label stock against the print head. In some situations, particularly where the supply roll of label stock is relatively large, when the feed roller first moves in order to begin movement of the label stock past the print head, the torque required to rotate the supply roll is sufficient enough to cause some slippage of the feed roller relative to the label stock. The result is typically seen as a compressed printed image on the label. Accordingly, it would be desirable to provide a media cassette which accounts for high torque loads generated by initial rotation of the supply roll.
As label stock cassettes get larger, installation and removal of the cassette becomes more difficult due to increased weight. It would therefore be desirable to provide a media cassette adapted for easier installation and removal, and it would also be desirable to provide a printer which is adapted for easier cassette installation, securing and removal.
In one aspect of the invention, a printer cassette installable in a printer includes a housing having a first media stock mount for positioning a roll of media stock thereon and a second media stock mount for holding a collection roll which receives a backing material of the media stock. An opening is provided in the housing, and an arm extends from the housing proximate to the opening for passing a loop of media stock therearound in position to be inserted into the printer along an intended path. The arm is biased into an extended position and retractable upon contact with a portion of the printer upon insertion of the cassette into the printer. Thus, the retractable arm locates the media stock in a proper orientation for being passed around the feed roller and stripper element of a print head assembly and therefor facilitates installation of the cassette into the printer. Various configurations of the arm are provided.
In another aspect of the invention, a printer includes a housing having a cassette receiving cavity, with a slot positioned along a peripheral surface of the cavity. A cassette latch member is positioned within the slot for holding a cassette within the cavity. A handle is connected with the latch member for effecting movement of the latch member. The latch member is movable between a latching position and a non-latching position, where the latch member extends from the slot into the cavity when in the latching position. The latch member is configured to engage a slot on the cassette when the cassette is inserted within the cavity. Preferably, the latch member includes a cam surface which cooperates with the cassette slot to pull the cassette into a secure position within the printer cavity.
In a further aspect of the present invention, a printer for printing labels includes a housing defining a cavity and a cassette positioned within the cavity, the cassette containing a supply roll of label stock. A print head assembly of the printer includes a label stock feed roller for feeding label stock past a print head of the assembly. A tensioner arm is positioned along a label stock path between the supply roll and the print head assembly. The tensioner arm contacts the label stock and is flexible to vary a label stock path according to a tension in the label stock during feed. The tensioner arm is positioned to for a normal label stock path which includes slack. When the torque required to move the supply roll and thus the tension of the label stock between the feed roller and the supply roll exceeds a certain level, the tensioner flexes or moves to allow the slack to be fed past the print head in order to reduce or prevent compressed printed images.